Search code examples
calgorithmrandomsrand

Avoiding Repeated seed generation using srand()

I have a typical situation where I need to generate a batch of random numbers. I have used a loop which generates 100 random numbers on each pass:

for(int i=0; i<npasses; i++)
{
   srand(time(NULL)); //Initialize seed

   for(int j=0; j<100; j++)
      printf("%d ", rand()%10);

   printf("\n"); //New line after 100 numbers
}

Now, the inner loop executes in less than a millisecond. As a result, there is no change in the value of time(). This re-initializes the seed (srand()) to the same value and my random numbers are REPEATED..

Can anyone suggest a workaround/fix.

Solution

  • Set the seed once, before the loop.